I thought I'd let you know that I made a nice modern public domain version of the CLOS MOP specification.

Full faithfulness to the contents of the book has been a top priority, which was ensured by carefully auditing the new version against the actual book, so this is very complete and safe to use. Mobile support is already implemented, and offline support and further improvements are underway.

I think it's safe to say that most people would prefer to use this new version over any other previously existing versions. A cursory look at my version should easily convince most people of this.

(Note that all or almost all of the CSS validation "errors" (as seen when clicking on "✔ CSS3" at the bottom of the page) stem from the validator not yet supporting CSS variables, a widely supported feature in all modern standards-compliant browsers. I consider this a bug in the validator.)

(For the more retro souls among us, I'm working on adding a "barren" preset to the preferences page, to make it possible to disable most features, resulting in a look more similar to the older obsolete versions.)